Oscillation device



Match 28, 1939. Y. ROCARD 2,151,300

OSCILLATION DEVICE Filed May 15, 1956 5 L/ /6' f7 %j v +8 n ATTORNEY Patented Mar. 28, 1939 UNITED STATES PATENT OFFICE pagnie Generale dc corporation of France Application May 13,

Telegraphic Sans Fil, a

1936, Serial No. 79,415

In France July 10, 1935 3 Claims.

The present invention consists in improvements in oscillator tubes or valve circuits, more particularly adapted to short and ultra-short waves. The object of the invention, on the one 5 hand, is to provide oscillators insuring greater frequency stability, and, on the other hand, oscillators of greater power than known types, and which are adapted to be coupled more easily with other circuit elements. In one embodiment, the

0 invention is used in a superheterodyne receiver comprising a separate oscillator tube whose operation will be accurate down to the smallest wavelengths capable of being amplified with electron tubes.

The invention consists essentially in an oscillator tube whose tuned circuit is connected to the plate and is coupled with a grid inductance which is connected to ground through a capacity which may be regulated to a value close to that which tunes this grid inductance to the frequency that is used, with due consideration'for the couplings provided with other circuits in the assembly, the point of junction between the grid inductance and the grid capacity being used either for connection to a source of radio frequency signals, such as an antenna or RF stage, with a view to insuring a frequency change or else for furnishing to. another circuit the frequency of the said oscillator or for any other desired association with outside circuits.

The advantages inhering in the invention are that by the aid of such an arrangement, in addition to frequency stabilization such as disclosed in French Patent No. 783,521, filed March 22, 1934, there is obtained a far larger oscillatory power output in the case of ultra-short waves, the upper limit of the frequencies for which oscillation is possible being raised. Moreover, the qualities of the oscillator are preserved in their entirety when the oscillator is connected in a way as disclosed, stray capacities thus introduced having no other action than that of altering the tuning of the grid capacity, whereas in the circuit organizations known in the prior art the said stray capacities make it impossible to use the oscillator in question under conditions insuring satisfactory efficiency.

It is by no means necessary in this invention that the tuning capacity in the grid circuit should be tuned to the working frequency, it being understood that this regulation may be fixed at will and that the user of the apparatus, at his own discretion, may find the point of maximum power output of the oscillator or the maximum responsiveness in an autodyne circuit scheme or any other quality.

It will also be understood that the invention may be used with other wave-lengths in which case it offers some advantages from the viewpoint of facility of adjustment; but it is in connection with work on ultra-short waves where the invention proves most useful, because of the increase of power resulting therefrom of the oscillator, because of the increase in the practical frequency range, and also because of the suppression of the troublesome action of stray capacities in the coupling circuits.

For a better understanding of the invention reference is made to the accompanying drawing in which:

Fig. 1 is a schematic circuit diagram of a portion of an autodyne receiver embodying the invention, and

Fig. 2 is a schematic circuit diagram of a portion of a superheterodyne receiver embodying the invention.

Referring to Fig. l a vacuum tube oscillator L1 is shown in connection with an autodyne receiver the tube having a control grid l, a screen grid 2, cathode 4 and plate 3, the control grid and cathode being connected by a resistor 5. Connected between grid l and ground is a series resonant circuit including coil 6 and adjustable condenser I which may be adjusted to make this circuit resonant to a desired frequency. As shown the antenna A is connected to the lower end of coil 6 and in a receiver, would supply the signal voltage to the grid circuit. The parallel resonant circuit 8 is connected to the plate, as is also the resonant circuit 9, which with its coupled circuit I0 is made resonant to the beat frequency. The signal energy of circuit It] may be detected or further amplified by any well known detection or amplifier device. The coil of circuit 8 may be inductively coupled to coil 6 to provide the required feedback of energy to the grid circuit.

Fig. 2 shows an oscillator L1 arranged the same as in Fig. 1 except that the lower end of coil 6 is directly connected, as by a lead II with the inner grid I2 of a vacuum tube L2, which in the case of a superheterodyne receiver, serves as a first detector. The outer grid M of this tube may be connected to the high potential end of the parallel resonant circuit l8 connected to antenna A. A screen grid I3 having a positive voltage may surround the signal grid [4 as shown. The output circuit I6 connected to plate l5-as well as itscoupled circuit H are preferably made resonant to the desired intermediate frequency,

the signal energy of circuit I! being detected or further amplified and detected, by any of the means well known to those skilled in the art. A superheterodyne receiver of the type shown is found to be highly eificient for the reception of ultra-short waves.

Having described my invention, it will be understood that it is not limited to the specific embodiments shown, but embraces all embodiments such as come within the scope of the following claims.

What I claim is:

1. A radio receiver comprising the combination of a vacuum tube having a cathode, a grid and a plate, an output circuit connected to said plate and having a first resonant circuit tuned to a desired oscillation frequency and a second resonant circuit tuned to the beat frequency, a series resonant circuit tuned to said desired frequency including a coil and condenser connected between said grid and ground, an aerial, a direct connection between said aerial and the common point of said coil and condenser and a feedback coupling between said output circuit and said series resonant circuit.

2. A radio receiver comprising the combination of a vacuum tube having a cathode, a grid and a plate, a circuit connected to said plate and resonant to the oscillation frequency, a series resonant circuit comprising a coil and condenser connected between said grid and ground and resonant to the oscillation frequency, a feedback coupling between said plate circuit and said series resonant circuit, a second tube comprising a cathode, two control grids and an anode, an output circuit resonant to the intermediate frequency connected to said anode, a circuit having one end connected to the common terminal of said coil and condenser and its other end to one of said control grids and a source of radio frequency signal voltage connected to the other of said control grids.

3. In a device of the class described, the combination of a circuit adapted to transmit currents of radio frequency, a vacuum tube oscillator having a series resonant grid circuit comprising an inductance and a variable condenser which constitute the frequency determining elements of said circuit, one terminal of said condenser being connected to ground, a plate circuit coupled to said inductance whereby to generate oscillations of a desired frequency, and a connection between the first named circuit and the common terminal of said inductance and condenser.

YVES ROCARD, 

